Herpes simplex encephalitis

• Infection of the brain parenchyma by HSV, with a predilection for temporal lobes

Presentation

• Fever
• Headache
• Altered level of consciousness
  • Personality and behavioural changes
• Focal neuro deficits
• Seizures
• Rapidly progressing and can lead to coma

Investigations

• Imaging
  • CT head usually normal
  • MRI head can show T2 signal change in temporal lobes
• Lumbar puncture
  • Elevated protein
  • Lymphocytosis (10-1000 WBCs)
  • Erythrocytes in 80% of cases ("hemorrhagic necrotizing meningoencephalitis")
  • Normal or slightly low glucose
  • HSV PCR is confirmatory
• EEG
  • Spikes and slow waves over involved areas
  • Periodic lateralized epiieptiform discharges (PLEDs)
  • Usually predominately over involved termporal lobe

Management

• Acyclovir 10mg/kg q8h IV for 14 days
  • Ensure adequate hydration and adjust for renal function